physic
May 26, 2012, 03:05 PM
3x y=15
4x-3y=7
xy=\frac {15}{3}
xy=5
x=\frac {7+3y}{4}
\frac {7+3y}{4}y=5
\frac {3y^2){4}+\frac {7y}{4}-5=0
a=\frac {3}{4}
b=\frac {7}{4}
c=-5
y=\frac{-b\pm\sqrt{b^2-4ac}}{2a}
physic
May 26, 2012, 03:10 PM
3x y=15
4x-3y=7
xy=\frac {15}{3}
xy=5
x=\frac {7+3y}{4}
\frac {7+3y}{4}y=5
\frac {3}{4}y^2+ {\frac {7}{4}y-5=0
a=\frac {3}{4}
b=\frac {7}{4}
c=-5
y=\frac{-b\pm\sqrt{b^2-4ac}}{2a}
\frac {3}{4}y^2+ {\frac {7}{4}y-5=0